This invention relates to powder metallurgy and, more particularly, to a powder metallurgy method for enhanced high temperature stability and hot workability of a burn-resistant titanium alloy.
Titanium alloys are known and used for manufacturing a variety of different aerospace components. Typically, the titanium alloy is cast into an ingot that is then formed into a billet, sheet, bar, or the like that is then formed into a component. At elevated temperatures, the titanium alloy typically forms alpha-titanium phase precipitates that embrittle the component and thereby undesirably limit a maximum use temperature of the component. Additionally, known titanium alloys are susceptible to cracking during hot working processes used to form mill products and components. Cracking limits conversion methods and reduces raw material yields, thereby increasing the expense of making the components.
One proposed solution to the problem of embrittlement and cracking during hot working is to add carbon to the titanium alloy to suppress formation of the alpha-titanium phase precipitates and improve the hot workability of the alloy. Presently, one drawback preventing widespread use of adding carbon is that the cast ingot processing method results in formation of large carbide phases that ultimately reduce fatigue performance of the component to undesirable levels. Adding less carbon to avoid the large carbide phases significantly reduces the effectiveness of the carbon for suppressing the alpha-titanium phase precipitates and improving the hot workability of the alloy. Thus, there has yet to be found a suitable combination of processing and composition for achieving a desirable combination of properties.
Accordingly, there is a need for a method of forming a component from a titanium alloy that includes carbon such that the component has a desired level of alpha-titanium phase suppression, fatigue performance, and resistance to cracking during hot working. This invention addresses those needs while avoiding the shortcomings and drawbacks of the prior art.